diff --git a/plugins/InspectionGadgets/src/META-INF/plugin.xml b/plugins/InspectionGadgets/src/META-INF/plugin.xml
index 92a7411c19b7..4164890aadfa 100644
--- a/plugins/InspectionGadgets/src/META-INF/plugin.xml
+++ b/plugins/InspectionGadgets/src/META-INF/plugin.xml
@@ -603,7 +603,7 @@
                      groupKey="group.names.control.flow.issues" enabledByDefault="false" level="WARNING"
                      implementationClass="com.siyeh.ig.controlflow.DefaultNotLastCaseInSwitchInspection"/>
     <localInspection language="JAVA" shortName="DoubleNegation" bundle="com.siyeh.InspectionGadgetsBundle" key="double.negation.display.name"
-                     groupBundle="messages.InspectionsBundle" groupKey="group.names.control.flow.issues" enabledByDefault="false"
+                     groupBundle="messages.InspectionsBundle" groupKey="group.names.control.flow.issues" enabledByDefault="true"
                      level="WARNING" implementationClass="com.siyeh.ig.controlflow.DoubleNegationInspection"/>
     <localInspection language="JAVA" shortName="DuplicateBooleanBranch" bundle="com.siyeh.InspectionGadgetsBundle"
                      key="duplicate.boolean.branch.display.name" groupBundle="messages.InspectionsBundle"
diff --git a/plugins/InspectionGadgets/src/com/siyeh/ig/controlflow/DoubleNegationInspection.java b/plugins/InspectionGadgets/src/com/siyeh/ig/controlflow/DoubleNegationInspection.java
index d6c863495dd7..7bdfe25e6e9e 100644
--- a/plugins/InspectionGadgets/src/com/siyeh/ig/controlflow/DoubleNegationInspection.java
+++ b/plugins/InspectionGadgets/src/com/siyeh/ig/controlflow/DoubleNegationInspection.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2011 Bas Leijdekkers
+ * Copyright 2006-2012 Bas Leijdekkers
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -40,6 +40,11 @@ public class DoubleNegationInspection extends BaseInspection {
     return InspectionGadgetsBundle.message("double.negation.problem.descriptor");
   }
 
+  @Override
+  public boolean isEnabledByDefault() {
+    return true;
+  }
+
   @Nullable
   protected InspectionGadgetsFix buildFix(Object... infos) {
     return new DoubleNegationFix();
@@ -117,7 +122,7 @@ public class DoubleNegationInspection extends BaseInspection {
       registerError(expression);
     }
 
-    private static boolean isNegation(PsiExpression expression) {
+    private static boolean isNegation(@Nullable PsiExpression expression) {
       expression = ParenthesesUtils.stripParentheses(expression);
       if (expression instanceof PsiPrefixExpression) return isNegation((PsiPrefixExpression)expression);
       if (expression instanceof PsiPolyadicExpression) return isNegation((PsiPolyadicExpression)expression);